This invention is directed to the providing of a solar heat apparatus which is designed for use with a water storage type system. Several types of water storage solar energy panels are known for use in conjunction with a water storage tank; however, the known type generally comprises structures which form covers for bodies of water and essentially function as a thermally insulative covering. None of the previously known structures incorporate a capacity for affecting control over the transfer of the solar energy to the water or over conversion of solar radiation to heat energy. Most of the known structures are of a type designed for either floating on the surface of water and providing heat transfer through the side walls of the structure or are of a type in which the water passes through a cavity within the structure with the solar radiation directly heating the water. Examples of the former type of structure are disclosed in the patents issued to Gerlach, U.S. Pat. No. 3,984,881; Forman, et al, U.S. Pat. No. 3,984,882; Roberts, U.S. Pat. No. 4,022,187 and Smith, U.S. Pat. No. 3,893,443. An example of the latter type of water storage tank solar energy system is shown by Voelker, U.S. Pat. No. 4,079,726.
Gerlach discloses a circular polyethylene panel which traps the heat of the sun by a thermally insulating air space formed within the body of the panel and may be of a color to enhance radiation absorption. The panel also acts to provide a covering for the body of water to prevent substantial heat loss from the pool. Forman discloses a similar circular plastic frame which possesses a channel running through the interior of the frame. Plastic sheets are fastened to the upper and lower edges of the frame, thus creating an enclosed cavity. The sheet itself has air filled interstices distributed about it due to its woven construction. Roberts also discloses a solar heating apparatus which is used as a pool cover in which a plurality of geometrically shaped units which may be attached to one another in a geometric pattern to form a large area cover. Each unit includes an upper and lower panel of plastic material, the upper one being transmissive of solar radiation and the lower being opaque. These plastic panels are joined at their peripheries to provide a thermal compartment between the opposing panel surfaces. Smith also discloses a floating solar heater in which the walls form a shallow chamber of substantially dead air space. All of the above patents feature enclosed panel structures featuring an upper and lower plastic sheet layer. Additionally, each of the patents rely on the transmission of heat from the enclosed air space to the body of water through the exchange of heat from the lower panel of the solar heating apparatus and furthermore, none of these structures have any means of affecting control over the conversion of solar radiation to heat energy or subsequent transfer of heat energy to or from the body of water that acts as a storage tank.
The other type of system which has utilized a water storage system is disclosed in Voelker. This system comprises a solar collector whereby the water of the pool is heated by circulation through the collector. This collector comprises a solar cover having upper and lower sheet surfaces forming channels through which the water is circulated.
The known structures for this purpose as illustrated in these patents are somewhat inefficient in preventing the loss of heat energy from the body of water back into the atmosphere due to their geometric configuration. They also provide for extremely slow heating of the water since they either depend on the direct conversion of solar radiation in the water or transfer of heat through a plastic sheet that has a low heat transfer characteristic or depend upon the circulation of the water between the two sheets of plastic as in Voelker. Additionally, the known structures do not have any means for controlling the amount of energy transferred to the water. Therefore, while the above noted structures are capable of providing a storage system for solar energy, they do not accomplish this objective in an efficient and selectively controllable manner.